I last replaced them with the plugs about 4 years/60-70k miles ago. I bought platinum plugs I if I remember correctly, so I still got some life on those. The car (2001 Buick Regal) is still in good ...
I ride a Piaggio scooter with a single cylinder engine. Recently I broke down and the engine wouldn't restart. It turned out the spark plug was stuffed. How can I ensure that doesn't happen again?